Wednesday, 16 November 2011

building the world's most iconic viking ship, part 3

So in our next installment in Viking boatbuilding we take the planks that were previously cleft, rough hewn and planed and trial fit them to the boat. Each and every board is different and is an exact replica of a particular board on the original ship. This is the office with the masterplan and to the left you can see scaled versions of each plank.

These are then turned into full scale plans which are taken out to the rough planks, drawn around and the profile cut out. This is Jan finishing  a plank before trial fitting for the first time. Most planks have raised sections which will be used later for lashing the ribs to.

Next we take these simple but very effective clamps
and trial fit the board in place.

Working along the plank I bend it to shape whilst Jan applies the powerful clamps, once the base of the board is clamped tightly we can twist the outside edge to check it will take the correct shape. It is not so much a bend as a twist in each board that gives the boat it's shape. You can see here the clamp with the rope is pulling the bow end inwards and the stern end is pulled outwards and downwards giving about 15 degrees of twist on this board, it will get a little more later.

 We have two datum lines to check the shape against, a row of pins set into the keel and a taught wire stretched above the ship. Using these two as measuring points it is possible to triangulate out to set each board in precisely the right place, we worked to a tolerance of ±5mm. Once each board was in it's final place the props underneath were fixed holding it's position.

Once we were happy with the trial fitting and had done any final rough shaping the board went into the steamer for 1 hour 20 minutes. When it comes out you have about a minute during which it moves very easily and then a couple of minutes for fine adjustment so everything has to be planned and to hand and everything happens quickly.

By the time the plank Jan and I had been working on was ready in the steamer it was already dark, it starts going dark at 3.30pm we did have big floodlights to work under sorry about dodgy pic quality.

Here the plank is in place and Jan is just tweaking the final line, you can clearly see the twist with the two ends of the plank being maybe 20 degrees out of line. We took the top and bottom corners 10mm further than they will end up expecting them to relax slightly when the pressure is taken off.

Now the board stays in place overnight after which time it's shape is set, it can be removed and very precise fitting work done, planing the joint to that it fits without the slightest gap. Once that is done it's time to rivet it in place, and that riveting, the whole essence of clinker boat building, is the next post.

1 comment:

  1. John thorgrimson2 March 2012 at 16:44

    Wonderful start, when will the ship be finished?